Recently, there is an increasing demand for a small-sized camera module used for an image input device for an information terminal such as a surveillance camera or a video tape recorder, as well as a variety of multimedia fields including a notebook-sized personal computer, a camera phone, a personal digital assistant (PDA), a smart-phone, and a toy.
As a pixel size of a sensor applied to the camera module becomes smaller and smaller and a height of the module is reduced, there is an urgent demand for development of a mounting structure for preventing inflow of foreign substances and achieving mechanical reliability of the camera module against a tilt or shift of an optic axis of a lens.
FIG. 1 is a view illustrating an image sensor and an IR (Infrared) filter attached to a printed circuit board (PCB) according to the prior art.
As shown in FIG. 1, according to the prior art, the image sensor 2 is bonded to the PCB 1 and thereafter the IR filter 3 coupled with a cover glass 4 is attached to a top of the PCB 1 so as to prevent contamination due to foreign substances and block infrared rays.
In this case, a space between the image sensor 2 and the IR filter 3 is sealed. However, air present in the sealed space expands while an adhesive (Epoxy/Glue/Bond) is thermally strengthened, thus causing an opened sealing or a tilt between the IR filter 3 and the cover glass 4.
Further, a reduction in adhesive strength between the IR filter 3 and the cover glass 4 may deteriorate mechanical reliability of the camera module, and may cause inflow of foreign substances between the image sensor 2 and the IR filter 3 because of the opened sealing.